1.0 Field of the Invention
The present invention relates to the field of moving user real-time data within a communication network and, more particularly, to a system which moves data within a communication network, such as the Internet, without revealing the identity of the initiator of the data, nor the identity of the receiver of the data, nor the content of the data.
2.0 Description of the Prior Art
The present invention is concerned with the right to privacy involved in electronic communication which may be better described by first discussing other forms of more commonly known communications.
For example, letters sent through the Post Office are usually in an envelope marked with the sender's and recipient's addresses. The general public trusts that the Post Office does not peek inside the envelope, because the contents are private. The general public also trusts that the Post Office does not monitor who sends mail to whom, because that information is also considered private.
These two types of sensitive information, the contents of an envelope and its addresses, apply equally well to electronic communication over the Internet. As the Internet becomes an increasing important part of modern day communication and electronic commerce, protecting the privacy of electronic messages also becomes increasingly important. Just like mail, electronic messages travel in envelopes, that is, electronic envelopes. Protecting the privacy of electronic messages requires both safeguarding the contents of their envelopes and hiding the addresses on their envelopes. Although communicating parties usually identify themselves to one another, there is no reason that the use of a public network, such as the Internet, ought to reveal to others who is talking to whom and what they are talking about. The first concern is traffic analysis, the latter is eavesdropping.
By making both eavesdropping and traffic analysis hard, the privacy of communication is protected. However, anonymity need not be completely maintained because two parties communicating with each other may need to identify each other. For example, if a Web surfer wants to buy something using the electronic equivalent of cash, the purchaser may need to be identified to properly establish the debt being incurred; however, the network need not know any of this information.
If an electronic envelope keeps its contents private, and the address on the envelope is also hidden, then any identifying information can only be inside the envelope. So for anonymous communication, we also should remove identifying information from the contents of an envelope. This may be called anonymizing a private envelope.
An anonymous connection is a communications channel for which it is infeasible to determine both endpoints, that is, which principal initiated the communication and whom receives the communication. The principal initiating the connection is the initiator, and the principal to whom the initiator connects is the responder. The present invention implements a mechanism for anonymous connections that operates below the application layer and supports a variety of Internet applications, wherein the application layer is the highest layer within the hierarchy of the protocols being used to perform the data transfer.
The usage of anonymous communication is known and generally referred to by the use of various terms in the art. For example, anonymous "Mixes" were introduced in 1985 as a store and forward mechanism for anonymously moving data through a network. These Mixes are not suitable for bidirectional real-time communication which is of importance to the present invention.
Anonymous remailers, also known in the art, have been used to store and forward mail from a sender to a recipient without revealing the identity of the sender to observers of the network. Different versions of these remailers use Mixes in a highly application specific way which limits their applicability for other uses.
Anonymous bidirectional real-time communication for Integrated Service Digital Network (ISDN) has also been explored, especially as in related phone switching means. Mixes are incorporated into an ISDN phone switch to permit anonymous connections between callers within the same ISDN switch. The usage of these anonymous connection means is dependent upon the characteristics of the ISDN phone switches which, in turn, has inherent limitations which, in turn, limit their usage.
The first mention of near real-time Mixes for the Internet appears in the Pipe-Net techniques also known in the art. Pipe-Net's design provides fixed bandwidth, low-capacity communications channels strongly protected against both active and passive traffic analysis attacks. However, the fixed bandwidth and low-capacity communication limit their usage. Further, to our knowledge this Pipe-Net's design has never been built, fully described, nor formally published.
The anonymizer, known in the art, provides weak protection against traffic analysis of World Wide Web (WEB) communications, by providing a centralized service that removes identifying information from the data stream. So called "Crowds" extends this approach to decentralize the proxy. However, the Anonymizer does not protect against passive attacks at the centralized proxy; whereas Crowds does not protect against global passive attacks. It is desired to provide a general purpose system that allows anonymous connections to move data through a communication network and that does not suffer the drawbacks of the prior art.